速生白榆的组织培养与快速繁殖

该文以速生白榆半木质化枝条为外植体,使用75%的酒精和0.1%HgCl_2消毒处理,外植体经过启动培养后,在增殖培养基中进行丛生芽诱导,将丛生芽切成单株进行生根诱导,最终建立起成熟的速生白榆组培快繁体系。结果表明:外植体最佳消毒处理组合为75%的酒精处理50 s+0.1%HgCl_2处理8 min,外植体污染率为17.3%,成活率为78%;将消毒处理过的外植体接种到启动培养基中,培养25 d,最终筛选出最适白榆外植体启动的培养基为MS+1.0 mg·L~(-1)6-BA+0.1 mg·L~(-1)IBA+30 g·L~(-1)蔗糖+6.5 g·L~(-1)琼脂,启动率高达87.5%;将经过启动培养后的外植体腋芽切下,接种到增殖培养基中进行丛生芽诱导,最终筛选出最佳增殖培养基为MS+0.5 mg·L~(-1)6-BA+0.1 mg·L~(-1)KT+0.1 mg·L~(-1)IBA+30 g·L~(-1)蔗糖+6.5 g·L~(-1)琼脂,继代周期25 d,增殖系数达6.2;将丛生芽切成单株,接种到生根诱导培养基中,筛选出最佳生根培养基为1/2 MS+0.1 mg·L~(-1)IBA+0.1 mg·L~(-1)IAA+30 g·L~(-1)蔗糖+6.5 g·L~(-1)琼脂,生根诱导30 d,生根率达97%。将生根苗在室外炼苗后,移栽到珍珠岩∶蛭石∶泥炭土体积比为1∶1∶1的混合基质中,成活率在90%以上。较高的增殖系数、生根率和移栽成活率可以降低生产成本,进而实现工厂化育苗。

Tissue culture and rapid propagation of fast-growing Ulmus pumila

The semi-lignified branches of fast-growing Ulmus pumila were used as explants, 75% alcohol and 0.1% HgCl₂ were used for disinfection. After initiation culture, the multiple shoots were first induced in the enrichment medium, and then cut into individual plants for rooting induction, and finally a tissue culture and rapid propagation system was established. The results showed that the optimal disinfection treatment combination of explants was 75% alcohol treatment for 50 s + 0.1% HgCl₂ treatment for 8 min, the contamination rate of explants was 17.3% and the survival rate was 78%. The sterilized explants were inoculated into the initiation medium and cultured for 25 d, and the most suitable medium for start-up of the explants was found to be MS + 1.0 mg L^-1 6-BA + 0.1 mg L^-1 IBA + 30 g L^-1 sucrose + 6.5 g L^-1 AGAR, with initiation rate up to 87.5%. After the initial culture, axillary buds of the explants were cut off and inoculated into the enrichment medium for multiple shoots induction. Finally, the optimal enrichment medium was selected as MS + 0.5 mg·L^-1 6-BA + 0.1 mg·L^-1 KT + 0.1 mg·L^-1 IBA + 30 g·L^-1 sucrose + 6.5 g·L^-1 AGAR, and the subculture cycle was 25 d with the increment coefficient as high as 6.2. The best rooting medium was 1/2 MS + 0.1 mg·L^-1 IBA + 0.1 mg·L^-1 IAA+ 30 g·L^-1 sucrose + 6.5 g·L^-1 AGAR, and rooting was induced for 30 d with a rooting rate of 97%. After seedling adaptation, the tissue culture seedlings of U. pumila were transplanted to mixed matrix with perlite:vermiculite:peat(volume ratio 1:1:1), and the survival rate reached above 90%. Higher increment coefficient, rooting rate and transplant survival rate can reduce production cost and realize factory seedling breeding.